Small-molecule JAK/IKK Kinase Inhibitors and JAK/ROCK/IKK Inhibitors for Treatment of Posterior Segment Disease via a Sustained Release PEA Bioerodible Implant.

Abstract

Purpose : For posterior segment disorders, a variety of kinases have been implicated in disease pathology, particularly kinases with pro-inflammatory activity such a Janus kinases (JAKs). Novel kinase inhibitors (deLong, et al. ARVO 2019) have been synthesized with low nanomolar inhibitory activity against the four JAK kinases in biochemical assays. In addition, some of these molecules possess low single-digit nM Rho kinase (ROCK) inhibitory activity, and others display low single-digit nM IκB kinase (IKK) inhibitory activity. These molecules were optimized for potency and compatibility with materials and processes used to formulate intravitreal implants, as otherwise small molecules are rapidly cleared after injection. To minimize injections, a 6 month duration of pseudo-first order release was desired.

Methods : In the course of Aerie's ROCK inhibition research, compounds were created with activity at JAK kinases. Optimization of JAK activity led to a series of pan-JAK inhibitors that also potently inhibited ROCK1 and ROCK2 and IKKb. Further optimization led to potent JAK inhibitors that lacked activity at the ROCK kinases. Cell-based JAK/IKK assays were developed based on phosphorylation of STAT3 and STAT5, as well as an IL23-stimulated mouse splenocyte assay. Modifications of a literature-described cellular NFkB assay were made to differentiate inhibition of IKK in cells from inhibition of JAK.

Results : Compounds A-E demonstrated single-digit nM activity at the desired kinases, with no discernable toxicity up to 100 µM. Two compounds also displayed cellular activity under 100 nM in one or more in vitro whole cell assay. Lead compound A was determined non-mutagenic in a preliminary Ames test, and demonstrated an extrapolated ~300 days of linear release kinetics in a PEA bioerodible implant. The molecules also demonstrated excellent thermal stability, although solubility was limited.

Conclusions : This proprietary class of cyclopropyl sulfonamide kinase inhibitors has demonstrated thermal stability under conditions needed for bioerodible implant manufacturing, low-single-digit nM to sub-nM activity against pro-inflammatory kinases, and nanomolar cell-based activity. As exemplified by Compound A, this class of inhibitors is under further study for intravitreal injection in a bioerodible implant for the treatment of posterior segment diseases.

This is a 2020 ARVO Annual Meeting abstract.